In this large cohort of MM patients who received upfront auto-HCT, we showed that a CD34+ cell dose of >2.5 × 106 cells/kg is associated with faster hematologic recovery and decreased length of hospitalization, as well as improved PFS and OS, compared to a CD34+ cell dose of ≤2.5 × 106 cells/kg. The gene discussed is CD34; the disease is Miyoshi myopathy.